Rotary hook mechanism for sewing machines



A ril 10, 1951 c. H. PETSKEYES 2,548,815

ROTARY HOOK MECHANISM FOR SEWING MACHINES Filed June 10, 1949 2Sheets-Sheet l ".4. P lm'n'r" IN V EN TOR.

5%4/ /43 A! fl k/56 x25 22% #13 Atwwey- April 10, 1951 c, PETSKEYES2,548,815 I ROTARY HOOK MECHANISM FOR SEWING MACHINES Filed June 10,1949 2 Sheets-Sheet 2 INVENTOR.

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Patented Apr. 10, 1951 ROTARY HOOK MECHANISM FOR SEWING MACHINES CharlesH. Petskeyes, Davenport, Iowa, assignor to Gellman ManufacturingCompany, Rock Island, 111., a corporation of Illinois Application June10, 1949, Serial No. 98,311

6 Claims. 1

This invention relates to rotary hook mechanism for sewing machines.More particularly the invention has to do With a simplified constructionfor associating a bobbin case with the rotary hook, this beingaccomplished in a manner such as will eliminate clashing between thebobbin case and the rotary hook, the contemplated construction having apredetermined tolerance or clearance between the bobbin case and thehook such as will eliminate interference of the rotary hook with respectto the bobbin case by reason of the admission between the bobbin caseand the rotary hook of foreign matter such as the lint from the thread.

In the operation of sewing machines there is always present a certainamount of lint from the thread. A certain amount of this lint betweenoperating parts of the machine finds its way between the bobbin and therotary hook. The constant accumulation of this lint will eventuallyinterfere with the proper operation of the hook requiring the bobbin androtary hook to be frequently disassembled to permit removal of theaccumulated lint, this being particularly so where the relation betweenthe bobbin case and the rotary case is of precision constructionallowing no tolerance or clearance between the operating parts of theassembly.

Not only is it an object of my invention to provide a simplifiedconstruction to prevent clashing between the bobbin case and the hook,but it is also an equally important object of the invention to arrangethe bobbin case with respect to the rotary hook in a manner such as willeliminate in a large measure interference of the rotary hook withrespect to the bobbin case caused by the accumulation of lint or piecesof thread. In accomplishing this latter object, I dispense with thenecessity of providing the usual thread cutters in the trackway of thehook.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of partsto be hereinafter described and claimed.

The invention will be best understood by reference to the accompanyingdrawings showing the preferred form of construction, and in which:

Fig. 1 is a top plan view of the hook and bobbin case in assembledrelation with respect to each other;

Fig. 2 is a bottom plan view of the same;

Fig. 3 is a sectional detail view taken substantially on line 33 of Fig.l;

Fig. 4 is a sectional detail view taken substantially on line 4-4 ofFig. 1;

Fig. 5 is a side elevational view of the same taken substantially online 5-5 of Fig. 1;

Fig. 6 is an exploded view illustrating the several parts comprising theinvention;

Fig. 7 is a plan view of the hook with the bobbin case removed;

Fig. 8 is a'plan view similar to Fig. 7, but illustrating a modifiedform of construction; and

Fig. 9 is a perspective view of the track ring embodied in the form ofconstruction shown in Fig. 8.

I prefer to accomplish the several objects ofmy invention by thepreferred forms of construction shown in the accompanying drawing. Inthis connection, the rotary hook is indicated at It]. In the bottom wallthereof is a centrally located opening II which receives the hookoperating shaft (not shown) of the sewing machine. This hook providesside walls I2 having a relatively flat top surface I3. This side wall I2provides a housing groove M.

The bobbin case is indicated at I5. This bobbin case provides alaterally extending flange I6, the peripheral edge ll of which extendsinto the groove I 4 and is retained therein by a gib ring I3 ofrelatively fiat formation and yieldably held in engagement with the topedge l3 of the wall R2 of the hook II]. This is accomplished byproviding in the gib ring I8 perforations I9 providing seats for taperededges 20 of connecting pins 2| projected through the perforations I9 andthrough the openings 22 formed in the side walls I2.

A spring plate 24 provides acentral hub 25 from which extend in oppositedirections with respect to each other the arms 26. These arms 26 areperforated as at 21 and through these perforations 21 extend the ends ofthe pins 2|. The ends of the pins 2I which project through theperforations 21 are each provided with a transverse opening 28 toreceive the angled end portions 29 of a connecting wire 30 whereby tocomplete the yieldable connection between the gib ring [8 and the hook I0.

The plate 24 is normally buckled in the form,

shown in Figs. 3 and 6 to bear the arms 26 against the angled endportions 29 of the connecting wire 30 and is of a degree of resiliencywhich, while efiectively yieldably holding the gib ring flatly incontact with the top edge I3 of the hook I0,

may be pressed back upon the bottom wall of the hook to facilitateremoval of the wire 30 with I5 provides a tracking groove 3! formed inthe.

underside 32 thereof. Positioned against the inside surface 33 of thewall I2 is a track ring 34, the top edge of which extends into thegroove M.

In the form shown in Figs. 1 to 6 inclusive, this track ring 34 is ofsplit formation, the ends 35 of which are spaced from each other andwhen in assembled position in the hook are disposed on opposite sides ofthe hook 36 and thread guide 31. The outer wall 38 of the flange itprovided by the formation of the groove 3% therein, normally rides onthe bottom wall 39 of the groove M, the top edge 40 of the track ringbeing slightly spaced from the flange 16. As shown in Figs. 3 and 4particularly, a clearance is provided between the outer wall 38 and theouter side surface of the track 34. Likewise, a clearance is providedbetween the wall 38 and the adjacent wall 4| of the wall i2. Theclearance between the track 34 and the wall 38 is less than theclearance between the walls 38 and 4|. Should the hook by reason ofcentrifugal force or by other mechanical agencies be caused to shiftlaterally with respect to its central axis, clashing of the flange l5against the wall 12 of the hook will be prevented by the engagement ofthe wall 38 with the track ring 34 and as there is a clearance betweenthe gib ring !8 and the flange id, no clashing between these parts cantake place.

Should thread or lint from the material being worked upon, find its wayinto the spaces provided by the several clearances hereinbefore referredto, such thread or lint will not be accumulated in such clearances so asto interfere with the rotation of the hook it but will be effectivelyworked out of the clearances without in any way retarding the rotationof such hook. The gib ring l8, being yieldably connected to the hook,will be permitted by the spring plate 24 to yield a suflicient distanceto free any thread or lint.

By the construction herein set forth, it is apparent that my improvedhook and bobbin case assembly is substantially non-clogging andnonclashing. The tracking ring 34 is connected to the hook by means ofsuitable rivets 42. It is preferably formed of such material as willbest serve the purpose.

In the modified form of construction shown in Figs. 8 and 9, the trackring '34 is formed in one piece and likewise adapted to be secured inplace by suitable rivets. In making this track ring 34 in one piece, thetop edge 35' tapers a predetermined degree to provide'a narrow section36' adapted to be disposed adjacent the hook 31 and thread guide 38'.The hook I8 is otherwise constructed in the same manner as that shown inFigs. 1 to '7 inclusive.

While I have illustrated and described the preferred form ofconstruction for carrying my invention into effect, this is capable ofvariation and modification without departing from the spirit of theinvention. I, therefore, do not wish to be limited to the precisedetails of construction set forth, but desire to avail myself of suchvariations and modifications as come within the scope of the appendedclaims.

Having thus described my invention, what I claim as new and desire toprotect by Letters Patent is:

l. For a, combination comprising a rotary hook having side wallsproviding adjacent the top edge thereof a groove, a bobbin case having aflange projecting into said groove and sai'd'flange providing in itsundersurface a groove, a *gib ring for retaining said flange in thegroove "of the rotary-hook, and a tracking Fmember carried by 4 the hookand having an edge portion engaging in the groove formed in theunderside of said flange, said flange being spaced from the adjacentside walls of the groove in said hook and the top edge of said trackingmember being normally spaced from the walls of the groove of said flangeso that upon lateral shifting movement between said bobbin case and saidhook said tracking member will restrain said flange from contacting saidside walls of the groove of said hook.

2. For a combination comprising a rotary hook having side wallsproviding adjacent the top edge thereof a groove, a bobbin case having aflange projecting into said groove and said flange providing in itsundersurface a groove, a gib ring for retaining said flange in thegroove of the rotary hook, and a tracking member carried by the hook andhaving an edge portion engaging in the groove formed in the underside ofsaid flange, there being a clearance between the flange and the sidewalls of the groove of said hook and between said flange and the saidgib ring and between the top edge of said tracking member and the grooveof said flange.

3. For a combination comprising a rotary hook having side wallsproviding adjacent the top edge thereof a groove, a bobbin case having aflange projecting into said groove and said flange providing in itsundersurface a groove, a gib ring for retaining said flange in thegroove of the rotary hook, and a tracking member carried by the hook andhaving an edge portion engaging in the groove formed in the underside ofsaid flange, said flange being spaced from the adjacent side walls ofthe groove in said hook and the top edge of said tracking member beingnormally spaced from the walls of the groove of said flange so that uponlateral shifting movement between said bobbin case and said hook saidtracking member will restrain said flange from contacting said sideWalls of the groove of said hook, and means for yieldably connecting thegib ring to the hook.

4. For a combination comprising a rotary hook having side wallsproviding'adjacent the top edge thereof a groove, a bobbin "case havinga flange projecting into said groove and said flange providing in itsundersurfac'e a groove, a gib ring for retaining said flange in thegroove of the rotary hook, a tracking member carried by the hook andhaving an edge portion engaging in the groove formed in the underside ofsaid flange, there being a clearance between'the flange and the sidewalls of the groove'of said hook and between said flange and the saidgib ring and between the top edge of said tracking member and the grooveof said flange, and means for yieldably connecting the gib ring to thehook.

5. For a combination comprising a hook member having a side wallproviding an internal groove, a bobbin case having a flange projectinginto the groove and having riding contact with the bottom wall of saidgroove, said flange providing in its underside a groove, anda ringprovided by said hook member and having an edge portion projecting intothe groove of said flange, there being a clearance between said flangeand the side wall of the groove of the hook member and a clearancebetween said top edge of said ring and the groove in said flange.

6. For a combinationcomprising a hook member having a. side wallproviding an internal groove, a bobbin case having a flange projecting 5into the groove and having riding contact with the bottom wall of saidgroove, said flange providing in its underside a groove, a ring providedby said hook member and having an edge portion projecting into thegroove of said flange, there being a clearance between said flange andthe side wall of the groove of the hook member and a clearance betweensaid top edge of said ring and the groove in said flange, and means foryieldably retaining said flange in the groove of saidhook member and forretaining the edge of said ring in the groove of saidflange.

CHARLES PETSKEYES.

The following references file of this patent:

6 REFERENCES CITED are of'record in the UNITED STATES PATENTS NumberNumber Germany Mar. 17, 1930

